Add healthchecks for dbsync to check current tip

[rdlrt]

[redoracle]

This is the new dbsync healtlh check:
#!/bin/bash

export PGPASSWORD=${POSTGRES_PASSWORD}
[[ $(( $(date +%s) - $(date --date="$(psql -qt -d ${POSTGRES_DB} -U ${POSTGRES_USER} -h ${POSTGRES_HOST} -c 'select time from block order by id desc limit 1;')" +%s) )) -lt 3600 ]] || return 1

[rdlrt]

The psql health check is added, ideally (low-priority future task) we should try and use curl http://127.0.0.1:8080 instead - which will also capture if dbsync is starting (while postgres is on tip) or doing ledger revalidation, while not really adding new blocks yet.

The problem encountered when doing so with official image as-is was that we didnt have basic utils (grep/sed/awk) to work with output of above URL for checking prometheus metrics